This invention relates generally to gas ranges and more particularly to a burner grate for improving burner simmer performance.
Household gas ranges typically have a number of gas burners located on the cooktop. A burner grate is situated over each burner for supporting a cooking utensil such as a pot or pan above the burner. The gas burners typically comprise a cylindrical burner head having a plurality of ports formed therein. A fuel-air mixture is discharged through the ports to produce the flame.
Adequate simmer performance is an important criterion in gas range burner design. Simmer performance is usually defined in terms of the minimum stable input rate of the burner; that is, the lowest input rate at which the burner is able to support a stable flame. However, the minimum stable input rate is not necessarily a good indication of simmer performance. This is evidenced by FIG. 1 which shows the local heat flux distribution across a typical cooking utensil (nine inch diameter) for five different input rates. In each instance, a sharp peak in flux occurs at the point where the flame impinges on the cooking utensil. As expected, heat fluxes are higher for the greater input rates of 8800 and 4800 BTU/hr. The peak heat flux for the input rate of 2500 BTU/hr is approximately 9000 BTU/hr/ft.sup.2 and occurs about 1.5 inches from the centerline. Reducing the input rate to 1500 BTU/hr, which is considered a simmer setting, results in only a slight reduction in the peak heat flux. Consequently, simmer performance is not significantly improved by this reduction in input rate. The local heat flux does begin to drop significantly as the input rate approaches 1000 BTU/hr, but most conventional gas burners are unable to support a stable flame at input rates this low.
Accordingly, there is a need for a means to improve the simmer performance of rangetop gas burners.